Cell penetrating liposomes for the oral delivery of peptide drugs

肽/蛋白质的经口给药经常由于它们在胃肠道中的不稳定性以及它们极低的再吸收速率而失败。在先前的资助中，对含有四醚脂质（TEL）的肽/蛋白质的脂质体载体系统进行了测试。先前的研究已经表明，与由常规磷脂组成的脂质体相比，这种脂质体在肠道中的稳定性大大提高（Uhl等人，2016年，Parmentier等人，2011年a）。此外，肽可以通过双重不对称离心以高载药量容易地掺入脂质体中（50-70%; Pantze等人，2014）。在Wistar大鼠的生物利用度研究中，发现与口服给药药物[奥曲肽（MW 1，170 Da）; Myrcludex B（MW 5，400 Da）和人生长激素（MW 23，500 Da）]的利用度相比，TEL脂质体中大分子药物的生物利用度显著增加（Parmentier et al.，2011 b，Uhl等人，2016和Parmentier等人，2014）。尽管取得了以往的成就，但仍有进一步改进的潜力。主要目标是确保在肠道中的最高吸收率，以便能够进行治疗应用。因此，在本后续项目中，必须进一步优化迄今已建立的系统。为此，TEL脂质体应包被细胞穿透肽（CPP）。已经测试了细胞穿透肽的脂质体细胞内转运（Torchilin等人，2001），并且存在关于可能的口服应用的第一数据（Kamei等人，2013年，2016年）。酸稳定的TEL脂质体和细胞穿透肽的组合在我们的初步实验中显示出增加的再吸收速率。得益于我们的新工艺，在脂质体生产过程中就可以进行包被，从而可以省略后续的清洁步骤。这使得能够在更大规模上进行高效、可重复和具有成本效益的生产。GLP-1类似物外消旋体由39个氨基酸组成，应用作模型物质。在这个项目中，将开发一个新的口头应用程序。Exenglycol（商品名Byetta）代表了一类新型的糖尿病治疗药物，2007年的销售额已经达到6.5亿美元。同时，这类物质的第二个代表（利拉鲁肽，诺和力）也已获得批准，突出了这类新型物质作为糖尿病治疗选择的重要性。应将艾塞那肽掺入用CPP包被的TEL脂质体中，以研究包封效率、脂质体大小、在各种条件下的稳定性、释放和加工成口服药物制剂的能力。最后，应在糖尿病小鼠模型中进行大鼠生物利用度研究和药理学概念验证试验。

The peroral administration of peptides / proteins frequently fails due to their instability in the gastrointestinal tract as well as their extremely low resorption rate. In a previous funding, a liposomal carrier system was tested for peptides / proteins containing Archaea tetraether lipids (TELs). Previous studies have shown an extremely improved stability of such liposomes in the intestinal tract compared to liposomes consisting of conventional phospholipids (Uhl et al., 2016, Parmentier et al., 2011a). Furthermore, peptides could be easily incorporated into the liposomes by means of dual asymmetric centrifugation in a high degree of drug loading (50-70%; Pantze et al., 2014). In bioavailability studies in Wistar rats, a significantly increased bioavailability of macromolecular drugs in TEL liposomes was found as compared to the availability of orally administered drugs [octreotide (MW 1,170 Da); Myrcludex B (MW 5,400 Da) and human growth hormone (MW 23,500 Da)] (Parmentier et al., 2011b, Uhl et al., 2016 and Parmentier et al., 2014). Despite previous achievements, the potential for further improvements still exists. The main goal is to ensure the highest possible resorption rate in the intestine in order to enable a therapeutic application. For this reason, the system established so far has to be further optimized in this follow-up project. For this purpose, the TEL liposomes shall be coated with cell-penetrating peptides (CPPs). Cell-penetrating peptides have already been tested for liposomal intracellular transport (Torchilin et al., 2001), and there exist first data on a possible peroral application (Kamei et al., 2013, 2016). The combination of acid-stable TEL liposomes and cell penetrating peptides showed in our preliminary experiments an increased rate of resorption. Thanks to our novel process, coating can already be carried out during liposome production, which allows omission of later cleaning steps. This enables an efficient, reproducible and cost-effective production on a larger scale. The GLP-1 analogue exenatide consists of 39 amino acids and shall be used as model substance. In this project, a new oral application shall be developed. Exenatide (trade name Byetta) represents a novel class of diabetes therapeutics and the sales were already 650 million dollars in 2007. Meanwhile, a second representative of this class of substances (Liraglutide, Victoza) has also been approved, highlighting the importance of this novel class of substances as a therapy option for diabetes therapy. Exenatide shall be incorporated into TEL liposomes coated with CPPs to investigate the encapsulation efficiency, liposomal size, stability under various conditions, release and process ability to an orally available drug formulation. Finally, a bioavailability study in rats and a pharmacological proof-of-concept trial shall be conducted in a diabetic mouse model.